As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multimode operations including communications, navigation, and tracking applications.

The EVA Software Defined Radio.
Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency-agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations.

Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR’s modular design permits implementation of the “same hardware at all Network Nodes” concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

This software-defined radio is under 3 in.3 (49 cm3) and weighs less than 4 oz. (113 g) with a power consumption averaging at 3 W (see figure). The EVA SDR design incorporates several innovations aimed at miniaturization without sacrificing any of its capabilities and still maintaining the lowest possible power consumption.

The SDR implements a range of technological solutions to achieve this goal. For instance, the SDR’s hardware and software were designed as a whole as opposed to being selected separately. In short, the hardware components were selected such that they can be heavily guided by the SDR’s software in order to minimize their power consumption. Additionally, the EVA SDR utilizes Lexycom’s Hardware Synergy Concept. Per this concept, the transceiver’s software divides the computational tasks performed by the device into small sub-tasks and designates these tasks to the most suitable hardware module for the task. In a sense, the SDR’s software performs micromanagement of the computed tasks well below the commonly used level of task assignment.

The EVA SDR also incorporates a dynamic waveform selection algorithm that minimizes the SDR’s power consumption based on the channel QoS. To do so, the SDR collects the channel characteristics on a regular basis while in the normal mode of operation and adjusts the modulation type, RF channel data rate, output power level, and some other characteristics of the transmitted signal based on the gathered QoS. This method results in, essentially, 1000s of continuously changing waveforms.

In sum, the EVA SDR bridges the gap that has historically inhibited the coexistence of flexibility, power efficiency, and miniaturization in the same mobile handset radio.

This work was done by Aleksey Pozhidaev of Lexycom Technologies for Johnson Space Center. For further information, contact the JSC Innovation Partnerships Office at (281) 483-3809.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Lisa Livdahl, CFO
Lexycom Technologies, Inc.
425 South Bowen Street, Unit 1
Longmont, CO 80501
Phone No.: (303) 774-7822
URL: www.lexycominc.com

MSC-25125-1